Self-etching cementitious substrate coating composition

ABSTRACT

Coating compositions for cementitious substrates may be made from a multistage latex polymer; silane; and a water-soluble acid, acid anhydride or acid salt capable of etching or otherwise reacting with the surface of the substrate to provide improved coating adhesion. The silane my may be present as a silane coupling agent distinct from the multistage latex polymer, or may be present as silane functionality on the multistage latex polymer. The coating compositions adhere well to cementitious substrates and have a self-etching capability which improves coating adhesion, especially near edges and corners.

BACKGROUND

Hard, abrasion resistant coatings are used over a variety of substrates,including cement, wood, and porous substrates. Particularly demandingsubstrates include horizontal substrates such as sidewalks, floor tiles,cement garage floors and decks. Unfortunately, many of the commerciallyavailable coatings in use today for these substrates suffer fromproblems such as poor adhesion, or poor water resistance (e.g.,“blushing”).

Cement and fiber cement substrates have an additional issue, in thatthey typically require hard, abrasion resistant coatings with excellentadhesion. In the past, this has been addressed by using higher-Tgpolymer systems. Unfortunately, volatile organic content (VOC) solventsgenerally must be used to achieve proper coalescence of higher-Tgpolymers. Consequently, there is an unmet need to develop acceptable lowVOC aqueous based coatings that are hard, blush resistant, abrasionresistant and offer excellent adhesion to cement and fiber cementsubstrates.

Some coatings also adhere poorly near edges and corners of cement andfiber cement substrates. The applied coating may initially appear to beproperly adhered but may later delaminate or otherwise prematurely fail.

SUMMARY

The present invention provides in one aspect aqueous coatingcompositions comprising a multistage latex polymer; silane; and awater-soluble acid, acid anhydride or acid salt capable of etching orotherwise reacting with the surface of a cementitious substrate so as toprovide improved coating adhesion. The multistage latex polymer includestwo or more polymer stages having different Tg values. The silane may bepresent as a silane coupling agent distinct from the multistage latexpolymer, or may be present as silane functionality on the multistagelatex polymer. The disclosed coating compositions adhere well tocementitious substrates and have a self-etching or other reactivecapability which improves coating adhesion, especially near edges andcorners.

In another aspect, the invention provides a method for preparing acoated article, which method comprises providing a cementitioussubstrate, coating at least a portion of the substrate with an aqueouscoating composition comprising a multistage latex polymer; silane; and awater-soluble acid, acid anhydride or acid salt, and allowing thecoating composition to harden.

In yet another aspect, the present invention provides coated articlescomprising a cementitious substrate having at least one major surface onwhich is coated a layer comprising an aqueous coating compositioncomprising a multistage latex polymer; silane; and a water-soluble acid,acid anhydride or acid salt.

The above summary of the present invention is not intended to describeeach disclosed embodiment or every implementation of the presentinvention. The description that follows exemplifies certain illustrativeembodiments. In several places throughout the application, guidance isprovided through lists of examples, which examples can be used invarious combinations. In each instance, the recited list serves only asa representative group and should not be interpreted as an exclusivelist.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and this specification. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic cross-sectional view of a coated fiber cementarticle;

FIG. 2 is a schematic cross-sectional view of a face-to-face pair ofcoated fiber cement articles with a protective liner therebetween;

FIG. 3 is a perspective view of a pallet of coated fiber cementarticles; and

FIG. 4 and FIG. 5 are differential scanning calorimetry (DSC) curvesrespectively showing Tg values for the multistage latex polymers ofExamples 1 and 2.

Like reference symbols in the various figures of the drawing indicatelike elements. The elements in the drawing are not to scale.

DETAILED DESCRIPTION

The recitation of a numerical range using endpoints includes all numberssubsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4, 5, etc.).

The terms “a,” “an,” “the,” “at least one,” and “one or more” are usedinterchangeably. Thus, for example, a coating composition that contains“an” additive means that the coating composition includes “one or more”additives.

The terms “board” or “fiberboard” refer to a generally planar componentsuitable for attachment to a building exterior surface, including lapsiding, vertical siding, soffit panels, trim boards, shingle replicas,stone replicas and stucco replicas.

The term “cementitious” refers to a substrate or material that comprisescement and has the properties or characteristics of cement, or thatcomprises a chemical precipitate, preferably of carbonates, having thecharacteristics of cement. Examples of cementitious substrates andmaterials include cement, burnished cement, concrete, polished concreteand cement fiberboard, and examples of places or applications wherecementitious substrates may be employed include floors (e.g., garagefloors), tiles (e.g., floor tiles), decks, boards and panels (e.g.,fiber cement boards), and the like.

The term “comprises” and variations thereof does not have a limitingmeaning where such term appears in the description or claims. Thus, acomposition comprising an ethylenically unsaturated compound means thatthe composition includes one or more ethylenically unsaturatedcompounds.

The term “coupling agent” refers to a composition that improves adhesionbetween a coating composition and a substrate on which a layer of thecoating composition has been applied and dried or otherwise hardened.

The terms “group” and “moiety” are used to differentiate betweenchemical species that allow for substitution or that may be substitutedand those that do not allow substitution or that may not be sosubstituted. Thus, when the term “group” is used to describe a chemicalsubstituent, the described chemical material includes substituted andunsubstituted groups, where the substituent groups may include O, N, Si,or S atoms, for example, in the chain (e.g., an alkoxy group) as well ascarbonyl groups and other substituent groups. The term “organic group”thus refers to a hydrocarbon (e.g., hydrocarbyl) group with optionalelements other than carbon and hydrogen in the chain, such as oxygen,nitrogen, silicon or sulfur. Representative organic groups includealiphatic groups, cyclic groups, and combinations of aliphatic andcyclic groups (e.g., alkaryl or aralkyl groups). The term “aliphaticgroup” refers to a saturated or unsaturated linear or branched organicgroup. For example, this term is used to encompass alkyl, alkenyl, andalkynyl groups. The term “alkyl group” refers not only to pure openchain saturated hydrocarbon alkyl substituents, such as methyl, ethyl,isopropyl, t-butyl, heptyl, dodecyl, octadecyl, amyl, 2-ethylhexyl, andthe like, but also to substituted alkyl groups having substituents knownin the art, such as hydroxy, alkoxy, alkylsulfonyl, halo, cyano, nitro,amino, carboxyl, and the like. The term “alkenyl group” refers to anunsaturated linear or branched hydrocarbon group with one or morecarbon-carbon double bonds and likewise may have substituents known inthe art. Non-limiting examples of alkenyl groups include groups such asvinyl, 1-propenyl, 2-propenyl, 1,3-butadienyl, 1-butenyl, 2-butenyl,1-pentenyl, 2-pentenyl, 1-hexenyl, 2-hexenyl, heptenyl, octenyl and thelike. The term “alkynyl group” refers to an unsaturated linear orbranched hydrocarbon group with one or more carbon-carbon triple bondsand likewise may have substituents known in the art. Non-limitingexamples of alkynyl groups include ethynyl, 1-propynyl, 2-propynyl,1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 1-hexynyl,2-hexynyl, heptynyl, octynyl and the like. The term “cyclic group”refers to a closed ring hydrocarbon group that can be classified as analicyclic group, aromatic group (aryl group), or heterocyclic group. Theterm “alicyclic group” refers to a cyclic hydrocarbon group havingproperties resembling those of aliphatic groups. Non-limiting examplesof alicyclic groups include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl and the like. The terms “aromaticgroup” or “aryl group” refer to a mono- or polycyclic aromatichydrocarbon group including phenyl or naphthyl groups. The term“heterocyclic group” refers to a closed ring hydrocarbon group in whichone or more of the atoms in the ring is an element other than carbon(e.g., nitrogen, oxygen, sulfur, etc.). When the term “moiety” is usedto describe a chemical compound or substituent, only the unsubstitutedchemical material is intended to be included. Thus, the phrase“hydrocarbyl moiety” refers to unsubstituted organic moieties containingonly hydrogen and carbon, and the phrase “alkyl moiety” refers to pureopen chain saturated hydrocarbon alkyl substituents such as methyl,ethyl, propyl, t-butyl, and the like.

A “latex” polymer means a dispersion or emulsion of polymer particlesformed in the presence of water and one or more secondary dispersing oremulsifying agents (e.g., a surfactant, alkali-soluble polymer ormixtures thereof) whose presence is required to form the dispersion oremulsion. The secondary dispersing or emulsifying agent is typicallyseparate from the polymer after polymer formation. In some embodiments areactive dispersing or emulsifying agent may become part of the polymerparticles as they are formed.

The phrase “low VOC” when used with respect to a liquid coatingcomposition means that the coating composition contains less than about10 weight % volatile organic compounds, more preferably less than about7% volatile organic compounds, and most preferably less than about 4%volatile organic compounds based upon the total liquid coatingcomposition weight.

The term “(meth)acrylic acid” includes either or both of acrylic acidand methacrylic acid, and the term “(meth)acrylate” includes either orboth of an acrylate and a methacrylate.

The term “multistage” when used with respect to a latex polymer meansthe polymer was made using discrete charges of one or more monomers orwas made using a continuously-varied charge of two or more monomers.Usually a multistage latex will not exhibit a single Tg inflection pointas measured using DSC. For example, a DSC curve for a multistage latexmade using discrete charges of one or more monomers may exhibit two ormore Tg inflection points. Also, a DSC curve for a multistage latex madeusing a continuously-varied charge of two or more monomers may exhibitno Tg inflection points. By way of further explanation, a DSC curve fora single stage latex made using a single monomer charge or a non-varyingcharge of two monomers may exhibit only a single Tg inflection point.Occasionally when only one Tg inflection point is observed, it may bedifficult to determine whether the latex represents a multistage latex.In such cases a lower Tg inflection point may sometimes be detected oncloser inspection, or the synthetic scheme used to make the latex may beexamined to determine whether or not a multistage latex would beexpected to be produced.

The terms “preferred” and “preferably” refer to embodiments which mayafford certain benefits, under certain circumstances. However, otherembodiments may also be preferred, under the same or othercircumstances. Furthermore, the recitation of one or more preferredembodiments does not imply that other embodiments are not useful, and isnot intended to exclude other embodiments from the scope of theinvention.

The terms “topcoat” or “final topcoat” refer to a coating compositionwhich when dried or otherwise hardened provides a decorative orprotective outermost finish layer on a substrate, e.g., a fiber cementboard attached to a building exterior. By way of further explanation,such final topcoats include paints, stains or sealers capable ofwithstanding extended outdoor exposure (e.g., exposure equivalent to oneyear of vertical south-facing Florida sunlight) without visuallyobjectionable deterioration, but do not include primers that would notwithstand extended outdoor exposure if left uncoated, viz., without atopcoat.

Referring to FIG. 1, a coated article 10 of the present invention isshown in schematic cross-sectional view. Article 10 includes a cementfiberboard substrate 12 with a first major surface 14. Substrate 12typically is quite heavy and may for example have a density of about 1to about 1.6 g/cm³ or more. Article 10 also includes at least one edgesuch as edge 15 between first major surface 14 and a side surface ofarticle 10 such as side surface 17. It will be understood by personshaving ordinary skill in the art that edge 15 may have a sharp orsomewhat rounded configuration but will in any event represent atransition region of relatively high curvature between major surface 14and side surface 17. Persons having ordinary skill in the art willunderstand that article 10 may have elongated and generally parallelside surfaces intersected by shorter end surfaces, and that these sideand end surfaces may be largely hidden when article 10 is installed,e.g., on a building. The first major surface 14 of substrate 12 may beembossed with small peaks or ridges 16 and valleys 18, e.g., so as toresemble roughsawn wood. Major surface 14 may have a variety of othersurface configurations, and may resemble a variety of building materialsother than roughsawn wood. The differences in height between peaks 16and valleys 18 in major surface 14 typically are much greater than thoseshown in FIG. 1; the thicknesses of layer 20 and topcoat 22 have beenmagnified in FIG. 1 for emphasis. The typical actual differences inheight between peaks 16 and valleys 18 in major surface 14 may forexample be about 1 to about 5 mm. An optional further layer or layers 20(which may for example be a sealer, primer or layers of both sealer andprimer) may lie atop surface 14. Layer 20 can provide a firmly-adheredbase layer upon which one or more firmly-adhered layers of topcoat 22may be formed, and may hide mottling or other irregularities (arising insome instances when article 10 is dried in a factory) which mayotherwise be visible on surface 14. If a primer, layer 20 may include ahigh Pigment Volume Concentration (PVC), e.g., about 45% or more. Layer20 is however not weather-resistant or decorative and is not designed orintended to serve as a final topcoat. Topcoat 22 desirably is bothdecorative and weather-resistant, and may be applied to article 10 atthe location where article 10 is manufactured or after article 10 hasbeen attached to a building or other surface. Topcoat 22 desirablyprovides a crush-resistant surface which withstands the forces that maybe imparted to article 10 during warehousing and shipping operationssuch as long-term storage and transporting of prefinished stackedcementboard to a jobsite. Topcoat 22 thus may provide reduced visualcoating damage and, consequently, less need for touch-up repairs orrecoating after article 10 has been attached to a building.

It can be difficult to obtain adequate adhesion of coatings such aslayer 20 or topcoat 22 to edge 15 or to corners (not shown in FIG. 1)where two edges such as edge 15 meet. This difficulty can be aggravatedwhen applying coatings to sawn fiber cement products, especially if thesawing process has burnished the product. The disclosed coatingcomposition may provide appreciably improved adhesion at such burnishedregions and at edges and corners proximate the burnished regions. Thedisclosed coating composition may also provide improved coating adhesionon the major surface or sides of a cement fiberboard substrate. In thedisclosed method, at least one edge such as edge 15 (and desirably allsuch edges, any corners where such edges meet, and yet more desirablythe sides and one or both major faces) of the cement fiberboardsubstrate such as substrate 12 is coated with the disclosed coatingcomposition. The disclosed coating compositions may conveniently beapplied to substrate 12 at the location where article 10 is manufacturedor may be applied after article 10 has been attached to a building orother surface.

FIG. 2 shows a schematic cross-sectional view of a face-to-face pair 24of coated fiber cement articles 10 a, 10 b whose embossed faces 14 a, 14b may be covered with optional primer, optional sealer or both primerand sealer (not shown in FIG. 2) and topcoats 22 a, 22 b. Topcoats 22 a,22 b face one another but are separated and protected somewhat fromdamage by protective liner 26 located between topcoats 22 a, 22 b. Thearrangement shown in FIG. 2 can provide better crush resistance whentall stacks of articles 10 are piled atop one another.

FIG. 3 shows a perspective view of a loaded pallet 30 including a pallet32 upon which has been loaded a plurality of eight board pairs 24 athrough 24 h. Optional strapping tape 34 helps stabilize loaded pallet32. Cross beams 35 sandwiched between upper horizontal platform 36 andlower horizontal platform 37 also stabilize loaded pallet 32. Personshaving ordinary skill in the art will recognize that other palletconfigurations may be employed. For example, the pallet may include morecross-beams 35 (e.g., three, four, five or more) or may omit lowerhorizontal platform 37. Persons having ordinary skill in the art willrecognize that pallet 32 may be loaded with fiber cement boards havingshapes other than the large siding boards shown in FIG. 3. For example,a pallet may be loaded with rows of side-by-side planks, soffit panels,trim boards, shingles, stone replicas, stucco replicas and otheravailable board configurations. Persons having ordinary skill in the artwill also recognize that the height of a loaded pallet 32 may vary, andfor example may be about 0.2 to about 2 meters.

The disclosed compositions may be applied to a variety of substrates,including cement, cement tiles, and fiber cement substrates. Thecomposition may also be applied to wood and wood substitutes. Thecompositions are particularly useful for coating cementitious substratesincluding cement floors and fiber cement articles. A variety of fibercement substrates may be employed. Fiber cement substrates typically arecomposites made from cement and filler. Exemplary fillers include wood,fiberglass, polymers or mixtures thereof. The substrates can be madeusing methods such as extrusion, the Hatschek method, or other methodsknown in the art. See, e.g., U.S. Patent Application Publication No. US2005/0208285 A1; Australian Patent Application No. 2005100347;International Patent Application No. WO 01/68547 A1; InternationalPatent Application No. WO 98/45222 A1; U.S. Patent ApplicationPublication No. US 2006/0288909 A1; and Australian Patent ApplicationNo. 198060655 A1. Fiber cement composites can include unprimed fibercement substrates and commercially available pre-primed or pre-paintedfiber cement substrates which may be topcoated as described below.Non-limiting examples of such substrates include siding products, boardsand the like, for uses including fencing, roofing, flooring, decking,wall boards, shower boards, lap siding, vertical siding, soffit panels,trim boards, shaped edge shingle replicas and stone or stucco replicas.One or both major surfaces of the substrate may be profiled or embossedto look like a grained or roughsawn wood or other building product, orscalloped or cut to resemble shingles. The uncoated substrate surfacetypically contains a plurality of pores with micron- or submicron-scalecross-sectional dimensions.

A variety of suitable fiber cement substrates are commerciallyavailable. For example, several preferred fiber cement siding productsare available from James Hardie Building Products Inc. of Mission Viejo,Calif., including those sold as HARDIEHOME™ siding, HARDIPANEL™ verticalsiding, HARDIPLANK™ lap siding, HARDIESOFFI™ panels, HARDITRIM™ planksand HARDISHINGLE™ siding. These products are available with an extendedwarranty, and are said to resist moisture damage, to require only lowmaintenance, to not crack, rot or delaminate, to resist damage fromextended exposure to humidity, rain, snow, salt air and termites, to benon-combustible, and to offer the warmth of wood and the durability offiber cement. Other suitable fiber cement siding substrates includeAQUAPANEL™ cement board products from Knauf USG Systems GmbH & Co. KG ofIserlohn, Germany, CEMPLANK™, CEMPANEL™ and CEMTRIM™ cement boardproducts from Cemplank of Mission Viejo, Calif.; WEATHERBOARDS™ cementboard products from CertainTeed Corporation of Valley Forge, Pa.;MAXITILE™, MAXISHAKE™ AND MAXISLATE™ cement board products from MaxiTileInc. of Carson, Calif.; BRESTONE™, CINDERSTONE™, LEDGESTONE™, NEWPORTBRICK™, SIERRA PREMIUM™ and VINTAGE BRICK™ cement board products fromNichiha U.S.A., Inc. of Norcross, Ga., EVERNICE™ cement board productsfrom Zhangjiagang Evernice Building Materials Co., Ltd. of China and EBOARD™ cement board products from Everest Industries Ltd. of India.

The disclosed articles may be coated on one or more surfaces with one ormore layers of the coating composition. For example, in one preferredembodiment the coating composition may include an optional primer layerand one or more topcoat layers. An optional sealer layer underneath theprimer layer may also be utilized, if desired. Preferably, the variouslayers are selected to provide a coating system that has good adhesionto the substrate and between adjacent layers of the system. If desired,the substrate may be pretreated with an aqueous solution containing awater-soluble acid or salt thereof as descried in more detail below.

Exemplary optional sealer layers include acrylic latex materials. Thetypical function of a sealer layer is to provide one or more featuressuch as improved adhesion, efflorescence blocking, water resistance orblocking resistance. Non-limiting sealers include unpigmented or lowpigment level latex coatings having, for example, between about 5 and 20weight % solids. An example of a commercially available sealer isOLYMPIC™ FC sealer from PPG Industries.

Exemplary optional primer layers include acrylic latex or vinyl primers.The primer may include color pigments, if desired. Preferred primershave a 60-degree gloss value of less than about 15, more preferably lessthan about 10, and optimally less than about 5 percent. Preferredprimers have a PVC greater than about 40%.

Other exemplary coating compositions for use under the coatings of thisinvention include those compositions and systems described in U.S.Patent Application Publication Nos. US 2007/0259166 A1 and US2007/0259188 A1, and International Patent Application Nos. WO2007/090132 A1 and WO 2007/089807 A1.

The disclosed compositions are formulated using multistage latexpolymers. Further details concerning multistage latex polymers arecontained in U.S. Patent Application Publication Nos. US 2006/0135684A1, US 2006/0135686 A1, US 2007/0110981 A1 and US 2009/0035587 A1. Themultistage latex polymer is preferably prepared through chain-growthpolymerization, using two or more ethylenically unsaturated monomers.Non-limiting examples of ethylenically unsaturated monomers includemonomers such as acrylic acid, methacrylic acid, methyl acrylate, ethylacrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methylmethacrylate, ethyl methacrylate, propyl methacrylate, butylmethacrylate, 2-ethylhexyl methacrylate, hydroxyethyl acrylate,hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutylmethacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate,glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylateglycidylether, 4-hydroxybutyl methacrylate glycidylether, acrylamide,methylacrylamide, diacetone acrylamide, methylol (meth)acrylamide,acrylonitrile, styrene, a-methyl styrene, vinyl toluene, vinyl acetate,vinyl propionate, allyl methacrylate, or mixtures thereof. If desired,the latex polymer may be formed using one or more acidic monomers. Forexample, the latex polymers may include up to about 5 weight %methacrylic acid or acrylic acid based on the total latex polymer weight(viz., the total polymer solids weight).

Exemplary multistage latex polymer compositions contain at least twopolymers of different glass transition temperatures (viz., different Tgvalues) and may be prepared via emulsion polymerization using many ofthe aforementioned monomers. In one preferred embodiment, the latex willinclude a first polymer stage (the “soft stage”) having a Tg less than30° C., e.g., between about −65 and 30° C., more preferably betweenabout −15 and 25° C., and most preferably between about −5 and 15° C.and a second polymer stage (the “hard stage”) having a Tg greater than30° C., e.g., between about 30 and 230° C., more preferably betweenabout 30 and 125° C., and most preferably between 60 and 100° C. Theratios of monomers in the disclosed multistage latex polymers may beadjusted to provide the desired level of “hard stage” or “soft stage”segments. The Fox equation may be employed to calculate the theoreticalTg of a polymer made from two monomer feeds:

1/Tg=W _(a) /T _(ga) +W _(b) /T _(gb)

-   -   where: T_(ga) and T_(gb) are the respective glass transition        temperatures of polymers made from monomers “a” and “b”; and        -   W_(a) and W_(b) are the respective weight fractions of            polymers “a” and “b”. Multistage latexes are conveniently            produced by sequential monomer feeding techniques. For            example, a first monomer composition is fed during the early            stages of the polymerization, and then a second different            monomer composition is fed during the later stages of the            polymerization. In certain embodiments it may be favorable            to start the polymerization with a high Tg monomer            composition and then switch to a low Tg monomer composition,            while in other embodiments, it may be favorable to start the            polymerization with a low Tg monomer composition and then            switch to a high Tg monomer composition.

A plurality of hard and soft stages may also be utilized. For example,in certain compositions it may be beneficial to polymerize two differentlow Tg soft stage monomer compositions after the hard stage polymer isformed. The first soft stage may be for example prepared with a monomerwhose homopolymer has a Tg close to room temperature (e.g., 20° C.) andthe second soft stage may be prepared with monomer whose homopolymer hasa Tg well below room temperature (e.g., less than 5° C.). While notintending to be bound by theory, it is believed that this second softstage polymer assists with improving coalescence of the latex polymerparticles.

It may be advantageous to use a gradient Tg latex polymer made usingcontinuously varying monomer feeds. The resulting polymer will typicallyhave a DSC curve that exhibits no Tg inflection points, and could besaid to have an essentially infinite number of Tg stages. For example,one may start with a high Tg monomer composition and then at a certainpoint in the polymerization start to feed a low Tg soft stage monomercomposition into the reactor with the high Tg hard stage monomer feed orinto the high Tg hard stage monomer feed. The resulting multistage latexpolymer will have a gradient Tg from high to low. A gradient Tg polymermay also be used in conjunction with multiple multistage Tg polymers. Asan example, a high Tg monomer feed (F1) and a low Tg monomer feed (F2)can be prepared. The process would begin by adding feed F1 into thelatex reactor vessel and initiating polymerization. After a certainperiod during the F1 feed, the feed F2 is added into F1 wherein the F2feed rate is faster than the overall feed rate of F1+F2 into the reactorvessel. Consequently, once the F2 feed into F1 is complete, the overallTg of the F1+F2 monomer feed blend will be a lower Tg “soft stage”monomer composition.

The disclosed multistage latex polymer compositions preferably includeabout 5 to about 95 weight percent soft stage polymer morphology, morepreferably about 50 to about 90 weight percent soft stage polymermorphology, and most preferably about 60 to about 80 weight percent softstage polymer morphology based on total latex polymer weight. Thedisclosed multistage latex polymer compositions preferably include about5 to 95 weight percent hard stage polymer morphology, more preferablyabout 10 to about 50 weight percent hard stage polymer morphology, yetmore preferably greater than 20 to about 40 weight percent hard stagepolymer morphology and most preferably about 25 to about 40 weightpercent hard stage polymer morphology based on total latex polymerweight.

The aforementioned multistage latex polymers are illustrative and othermultistage latex polymers may be used in the practice of this invention.For example, the multistage latex polymer may be prepared with a high Tgalkali-soluble polymer hard stage. Alkali-soluble polymers may beprepared by making a polymer with acrylic or methacrylic acid or otherpolymerizable acid monomer (usually at greater than 7 weight %) andsolubilizing the polymer by addition of ammonia or other base. Examplesof suitable alkali-soluble high Tg support polymers include JONCRYL™ 675and JONCRYL 678 oligomer resins, available from BASF. A low Tg softstage monomer composition or gradient Tg composition could then bepolymerized in the presence of the hard stage alkali-soluble polymer toprepare a multistage latex polymer. Another exemplary process forpreparing alkali soluble supported polymers is described in U.S. Pat.No. 5,962,571. For coating compositions containingacetoacetyl-functional polymers (particularly clear coatings), anitrogen-free base (e.g., an inorganic metal base such as KOH, CaOH,NaOH, LiOH, etc.) may be beneficial. If desired, the disclosed coatingcompositions may also contain non-silane-functional latex polymers,including non-silane-functional multistage latex polymers.

The disclosed multistage latex polymers may be stabilized by one or morenonionic or anionic emulsifiers (e.g., surfactants), used either aloneor together. Examples of suitable nonionic emulsifiers includetert-octylphenoxyethylpoly(39)-ethoxyethanol,dodecyloxypoly(10)ethoxyethanol,nonylphenoxyethyl-poly(40)ethoxyethanol, polyethylene glycol 2000monooleate, ethoxylated castor oil, fluorinated alkyl esters andalkoxylates, polyoxyethylene (20) sorbitan monolaurate, sucrosemonococoate, di(2-butyl)-phenoxypoly(20)ethoxyethanol,hydroxyethylcellulosepolybutyl acrylate graft copolymer, dimethylsilicone polyalkylene oxide graft copolymer, poly(ethyleneoxide)poly(butyl acrylate) block copolymer, block copolymers ofpropylene oxide and ethylene oxide,2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylated with ethylene oxide,N-polyoxyethylene(20)lauramide, N-lauryl-N-polyoxyethylene(3)amine andpoly(10)ethylene glycol dodecyl thioether. Examples of suitable anionicemulsifiers include sodium lauryl sulfate, sodiumdodecylbenzenesulfonate, potassium stearate, sodium dioctylsulfosuccinate, sodium dodecyldiphenyloxide disulfonate,nonylphenoxyethylpoly(1)ethoxyethyl sulfate ammonium salt, sodiumstyrene sulfonate, sodium dodecyl allyl sulfosuccinate, linseed oilfatty acid, sodium, potassium, or ammonium salts of phosphate esters ofethoxylated nonylphenol or tridecyl alcohol, sodiumoctoxynol-3-sulfonate, sodium cocoyl sarcocinate, sodium1-alkoxy-2-hydroxypropyl sulfonate, sodium alpha-olefin(C₁₄-C₁₆)sulfonate, sulfates of hydroxyalkanols, tetrasodiumN-(1,2-dicarboxy ethyl)-N-octadecylsulfosuccinamate, disodiumN-octadecylsulfosuccinamate, disodium alkylamido polyethoxysulfosuccinate, disodium ethoxylated nonylphenol half ester ofsulfosuccinic acid and the sodium salt oftert-octylphenoxyethoxypoly(39)ethoxyethyl sulfate.

One or more water-soluble free radical initiators typically are used inthe chain-growth polymerization of the multistage latex polymer.Initiators suitable for use in the coating compositions will be known topersons having ordinary skill in the art or can be determined usingstandard methods. Representative water-soluble free radical initiatorsinclude hydrogen peroxide; tert-butyl peroxide; alkali metal persulfatessuch as sodium, potassium and lithium persulfate; ammonium persulfate;and mixtures of such initiators with a reducing agent. Representativereducing agents include sulfites such as alkali metal metabisulfite,hydrosulfite, and hyposulfite; sodium formaldehyde sulfoxylate; andreducing sugars such as ascorbic acid and isoascorbic acid. The amountof initiator is preferably from about 0.01 to about 3 weight %, based onthe total amount of monomer. In a redox system the amount of reducingagent is preferably from 0.01 to 3 weight %, based on the total amountof monomer. The polymerization reaction can be performed at atemperature in the range of from about 10 to about 100° C.

The disclosed coating compositions may for example include a multistagelatex polymer in an amount of at least 10 weight %, at least 25 weight%, or at least 35 weight %, based on total composition solids. Themultistage polymer amount is less than 100 weight %, and may for examplebe less than 85 weight % or less than 80 weight %, based on totalcomposition solids.

The multistage latex polymer may include silane functionality andthereby provide both a multistage latex polymer and a silane in thedisclosed coating compositions. Silane functionality may for example beprovided in the multistage latex polymer by carrying out chain-growthpolymerization in the presence of a silane containing a functional groupcapable of copolymerizing with, and which copolymerizes with, a monomerfrom which the multistage latex polymer is formed. Exemplary suchsilanes include monomeric, dipodal and oligomeric silanes containing avinyl, allyl, (meth)acrylate or other ethylenically unsaturated group,or a mercapto group. Representative silanes include olefinic silanessuch as vinyltrialkoxysilane, vinyltriacetoxysilane,alkylvinyldialkoxysilane, hexenyltrialkoxysilane and the like, allylsilanes such as allyltrialkoxysilane, silane acrylates such as(3-acryloxypropyl)trimethoxysilane, γ-methacryloxypropyltrimethoxysilaneand the like, mercapto silanes such as 3-mercaptopropyltrimethoxysilane,3-mercaptopropyltriethoxysilane,s-(octanoyl)mercaptopropyltriethoxysilane,3-thiocyanatopropyltriethoxysilane,3-mercaptopropylmethyldimethoxysilane,bis[3-(triethoxysilyl)propyl]-tetrasulfide, andbis[3-(triethoxysilyl)propyl]-disulfide, vinyl silanes such as SILQUEST™A-151 vinyl triethoxysilane, A-171 vinyl trimethoxysilane, A-172vinyl-tris-(2-methoxyethoxy)silane, A-174γ-methacryloxypropyltrimethoxysilane, and A-2171 vinylmethyldimethoxysilane (available from Momentive Performance MaterialsInc), SIV9098.0 vinyltriacetoxysilane (available from Gelest Inc.) andthe like. Silanes with multiple functionality may also be used such asDYNASYLAN™ HYDROSIL 2929, an amino/methacrylate functional silane(available from Degussa).

The multistage latex polymer may also be made silane-functional bycombining the polymer with a silane having a functional group (e.g., anepoxy, amino or isocyanato group) and reacting the functional group withfunctionality (e.g., acetoacetoxy, carboxy or amino functionality) onthe already-formed latex polymer. Exemplary epoxy-functional silanesinclude silanes having the formula:

R₁Si(R₂)_(3-n)(OR₃)_(n),

where n is 1, 2, or 3, the R₁ group contains at least one epoxy groupand is alkyl, cycloalkyl, phenyl, cycloalkylalkyl, alkenylcycloalkyl,alkenylphenyl (e.g., benzyl), or phenylalkyl (e.g., tolyl). Each R₂group is independently hydrogen, alkyl, cycloalkyl, phenyl,cycloalkylalkyl, alkenylcycloalkyl, alkenylphenyl (e.g., benzyl),phenylalkyl (e.g., tolyl), or a silane oligomer, wherein each R₂ groupcan optionally include OR₃ groups or epoxy functionality. Each R₃ groupis independently hydrogen, alkyl, cycloalkyl, phenyl, cycloalkylalkyl,alkenylcycloalkyl, alkenylphenyl (e.g., benzyl), or phenylalkyl (e.g.,tolyl). Preferred epoxy-functional silanes have an average molecularweight of from about 140 to about 500 g/mole, more preferably from about150 to about 300. In one preferred embodiment, the molecular weight doesnot exceed a maximum of about 190 to about 250, n is 1 or 2, R₁ is analkyl group of 3 to 8 carbon atoms containing no more than one epoxygroup, and R₂ is a methoxy or ethoxy group.

Exemplary epoxy-functional silanes include β-(3,4epoxycyclohexyl)-ethyltrimethoxysilane (available from MitsubishiInternational Corporation as KBM303 and from Dow Corning as Z-6043),γ-glycidoxypropyltrimethoxysilane (available from MitsubishiInternational Corporation as KBM403 and from Dow Corning as Z-6040),γ-glycidoxypropylmethyldiethoxysilane (available from MitsubishiInternational Corporation as KBE402 and from Dow Corning as Z-6042),γ-glycidoxypropyltriethoxysilane (available from Dow Corning as Z-6041and from GE Silicones as SILQUEST™ A-187),γ-glycidoxypropylmethyldimethoxysilane (available from Dow Corning asZ-6044), 5,6-epoxyhexyltriethoxysilane (available from Gelest, Inc. asS144675.0), hydrolyzates of the above and the like.

Exemplary amino-functional silanes include silanes having the formula:

R₁—Si(R₂)_(3-n)(OR₃)_(n)

where n is 1, 2, or 3, the R₁ group contains at lest one amino group andis alkyl, cycloalkyl, phenyl, cycloalkylalkyl, alkenylcycloalkyl,alkenylphenyl (e.g., benzyl), or phenylalkyl (e.g., tolyl). Each R₂group is independently hydrogen, alkyl, cycloalkyl, phenyl,cycloalkylalkyl, alkenylcycloalkyl, alkenylphenyl (e.g., benzyl), orphenylalkyl (e.g., tolyl), or a silane oligomer, wherein each R₂ groupcan optionally include OR₃ groups or amino functionality. Each R₃ groupis independently hydrogen, alkyl, cycloalkyl, phenyl, cycloalkylalkyl,alkenylcycloalkyl, alkenylphenyl (e.g., benzyl), or phenylalkyl (e.g.,tolyl). Preferred amino-functional silanes have an average molecularweight of from about 140 to about 500, more preferably from about 150 toabout 300. In one embodiment, it is preferred that the number averagemolecular weight not exceed a maximum of about 190 to about 250, that nis 1 or 2, R₁ is an alkyl group having from 3 to 8 carbon atoms andcontaining no more than one amino group, and R₂ is a methoxy or ethoxygroup.

Exemplary amino-functional silanes includetrimethoxysilylpropyldiethylenetriamine,N-methylaminopropyltrimethoxysilane,aminoethylaminopropylmethyldimethoxysilane,aminoethylaminopropyltrimethoxysilane (available from Dow Corning asZ-6020), aminopropylmethyldimethoxysilane, aminopropyltrimethoxysilane,polymeric aminoalkylsilicone,aminoethylaminoethylaminopropyl-trimethoxysilane,aminopropylmethyldiethoxysilane, aminopropyltriethoxysilane,4-aminobutyltriethoxysilane, oligomeric aminoalkylsilane,m-aminophenyltrimethoxysilane, phenylaminopropyltrimethoxysilane,1,1,2,4-tetramethyl-1-sila-2-azacyclopentane,aminoethylaminopropyltriethoxysilane,aminoethylaminoisobutylmethyldimethoxysilane,benzylethylenediaminepropyltrimethoxysilane, hydrolyzates of the aboveand the like.

Acetoacetyl functionality may be incorporated into the multistage latexpolymer through the use of an acetoacetyl-functional olefinic monomersuch as acetoacetoxyethyl acrylate, acetoacetoxypropyl methacrylate,allyl acetoacetate, acetoacetoxybutyl methacrylate,2,3-di(acetoacetoxy)propyl methacrylate, 2-(acetoacetoxy)ethylmethacrylate (AAEM), t-butyl acetoacetate, and the like or combinationsthereof. The acetoacetyl-functional latex polymer may for example beprepared through chain-growth polymerization, using, for example AAEM. Apolymerizable hydroxy-functional or other active hydrogen containingmonomer may also be converted to the correspondingacetoacetyl-functional monomer by reaction with diketene or otheracetoacetylating agent (see, e.g., Comparison of Methods for thePreparation of Acetoacetylated Coating Resins, Witzeman, J. S.; DellNottingham, W.; Del Rector, F. J. Coatings Technology; Vol. 62, 1990,101 (and citations contained therein)). The latex polymer may forexample include at least about 0.5 weight % acetoacetyl functionality,about 0.5 to about 5 weight % acetoacetyl functionality, or about 2 toabout 7.5 weight % acetoacetyl functionality based on the total latexpolymer weight. Functionalized latex polymers are further described inU.S. Patent Application Publication Nos. US 2006/0135684 A1 and US2006/0135686 A1. When present, the acetoacetyl functional grouppreferably is incorporated into the latex polymer using2-(acetoacetoxy)ethyl methacrylate, t-butyl acetoacetate, diketene, orcombinations thereof.

The disclosed coating compositions may contain a multistage latexpolymer and a separate silane coupling agent that is not reacted with orreactive with the multistage latex polymer. Exemplary silane couplingagents include alkoxysilanes such as bis(triethoxysilylethane, 1,2bis(trimethoxysilyl)decane, (trimethoxysilyl)ethane andbis[(3-methyldimethoxysilyepropyl]-polypropylene oxide; carboxylatesilanes such as carboxyethylsilanetriol sodium salt; hydroxy silanessuch as bis(2-hydroxyethyl)-3-aminopropyl-triethoxysilane,triethoxysilylmethanol, N-(triethoxysilylpropyl)-o-polyethylene oxideurethane and N-(3-triethoxysilylpropyl)gluconamide; phosphate andphosphine silanes such as diethylphosphatoethyltriethoxysilane and3-trihydroxysilylpropylmethylphosphonate, sodium salt; and sulfonatesilanes such as 3-(trihydroxysilyl)1-1propane-sulfonic acid. The silanemay also be a polymeric silane such as triethoxysilyl modifiedpoly-1,2-butadiene From Gelest, Inc. and aminoalkyl silsesquioxaneoligomers from Gelest, Inc.

Practical considerations such as solubility, hydrolysis rate,compatibility with the coating composition, polymer stability, and thelike may be considered when selecting the structure and molecular weightof the silane and choosing whether to react the silane with a monomerfrom which the multistage latex polymer is found, or to react the silanewith functionality on the already-formed latex polymer, or to providethe silane as a separate silane coupling agent that is not reacted withor reactive with the multistage latex polymer. Each of these approachesor a combination of any two of them may be used if desired. Whether thesilane has been reacted into the multistage latex polymer during polymerformation, reacted onto the multistage latex polymer after polymerformation, or provided as a separate silane coupling agent, thedisclosed coating compositions may for example contain at least about0.2 weight %, at least about 0.5 weight %, or at least about 0.7 weight% silane, based on a comparison of the weight of silane startingmaterial to the latex polymer weight. The multistage latex polymer mayfor example contain less than about 10 weight %, less than about 6weight %, or less than about 4 weight % silane, based on a comparison ofthe weight of silane starting material to the latex polymer weight. Thedisclosed silane amounts may have to be adjusted upward for compositionsthat include silane-functional ingredients whose silane groups react(e.g., as a crosslinker) with a component in the coating composition andthereby become unavailable for surface coupling or other adhesionpromotion on a cementitious substrate.

As one exemplary embodiment, a multistage latex polymer with a silanatedsoft segment may be prepared by providing a monomer compositioncontaining 5 to 65 parts butyl acrylate, 20 to 90 parts butylmethacrylate, 0 to 55 parts methyl methacrylate, 0.5 to 5 parts(meth)acrylic acid, 0 to 20 parts AAEM and 0.1 to 2 parts olefinicsilane. A silanated hard segment may be introduced by providing amonomer composition including 0 to 20 parts butyl acrylate, 0 to 40parts butyl methacrylate, 45 to 95 parts methyl methacrylate, 0.5 to 5parts (meth)acrylic acid, 0 to 20 parts AAEM and 0.1 to 2 parts olefinicsilane. The olefinic silane may be reacted into either or both of thesoft and hard segments. Silane functionality may instead or in additionbe reacted onto the already-formed multistage latex polymer via reactionwith functionality on either or both of the soft and hard segments.

A variety of water-soluble acids and their salts may be used in thedisclosed coating compositions. The acid or acid salt may for examplehave a water solubility of at least 5 wt. %, at least 10 wt. %, at least20 wt. %, at least 50 wt. % or complete water miscibility. Exemplaryacids may be inorganic or organic acids, and if organic may be monomericor oligomeric. If desired, a precursor to the acid such as an acidanhydride, acid halide (including inorganic acid halides such as Lewisacids and organic acid halides), or ester can be used in place of or inaddition to the acid itself, e.g., to generate the desired acid in situ.Exemplary acids include carboxylic acids; sulfonic acids; phosphorusacids; nitric and nitrous acids; hydrogen halides such as hydrogenfluoride, hydrogen chloride, hydrogen bromide and hydrogen iodide; othermineral acids such as boric acid and sulfuric acid; silicic acids; andphenols. Exemplary water-soluble acid salts include sodium, potassium,lithium and ammonium salts, and various other water-soluble metal saltsincluding water-soluble magnesium, calcium and iron salts. Mixtures ofacids, acid anhydrides and acid salts may be employed, includingmixtures which buffer the pH of the disclosed coating compositions.

Exemplary carboxylic acids include acetic acid (C₂H₄O₂, CAS RN 64-19-7),maleic acid (C₄H₄O₄, CAS RN 110-16-7), citric acid (C₆H₈O₇, CAS RN77-92-0), formic acid (CH₂O₂, CAS RN 64-18-6) and benzoic acid (C₇H₆O₂,CAS RN 65-86-0). Exemplary carboxylic acid salts include sodium acetate(CAS RN 127-09-3), potassium acetate (CAS RN 127-08-2), lithium acetate(CAS RN 6108-17-4), ammonium acetate (CAS RN 631-61-8), sodium citrate(CAS RN 6132-04-3), potassium citrate (CAS RN 866-84-2 or 7778-49-6),lithium citrate (CAS RN 919-16-4), ammonium citrate (CAS RN 1185-57-5)and ammonium citrate dibasic (CAS RN 3012-65-5).

Exemplary phosphorus acids include phosphoric acid (H₃PO₄, CAS RN7664-38-2), pyrophosphoric acid (H₄O₇P₂, CAS RN 2466-09-03),polyphosphoric acid (H_(n+2)P_(n)O_(3n+1), CAS RN 8017-16-1), phosphonicacid (H₃PO₃, CAS RN 13598-36-2), phosphinic acid (H₃PO₂, CAS RN6303-21-5), ethyl phosphonic acid (C₂H₇O₃P, CAS RN 15845-66-6) andhypophosphoric acid (H₂PO₃, CAS RN 7803-60-3). Exemplary phosphorus acidsalts include ammonium dihydrogen phosphate (NH₄H₂PO₄, CAS RN7722-76-1), diammonium hydrogen phosphate ((NH₄)₂HPO₄, CAS RN7783-28-0), calcium dihydrogen phosphate (Ca(H₂PO₄)₂, CAS RN 7758-23-8),calcium monohydrogen phosphate dihydrate (CaHPO₄.2H₂O, CAS RN7789-77-7), calcium phosphate tribasic (Ca₃(PO₄)₂.H₂O, CAS RN7758-87-4), ferric phosphate (FePO₄, CAS RN 10045-86-0), lithiumorthophosphate (Li₃PO₄, CAS RN 10377-52-3), magnesium ammonium phosphatehydrate ((NH₄)MgPO₄, CAS RN 7785-21-9), magnesium hydrogen phosphatetrihydrate (MgHPO₄.3H₂O, CAS RN 7757-86-0), potassium dihydrogenphosphate (KH₂PO₄, CAS RN 7778-77-0), dipotassium hydrogen phosphate(K₂HPO₄, CAS RN 7758-11-4), dipotassium hydrogen phosphate trihydrate(K₂HPO₄.3H₂O, CAS RN 16788-57-1), potassium orthophosphate (K₃PO₄, CASRN 7778-53-2), potassium diphosphate (K₄P₂O₇, CAS RN 7320-34-5), sodiumdihydrogen phosphate (NaH₂PO₄, CAS RN 7558-80-7), sodium phosphatemonobasic monohydrate (NaH₂PO₄.H₂O, CAS RN 10049-21-5), disodiumhydrogen phosphate (Na₂HPO₄, CAS RN 7558-79-4), disodium phosphatedibasic dodecahydrate (Na₂HPO₄.12H₂O, CAS RN 10039-32-4), disodiumphosphate dibasic heptahydrate (Na₂HPO₄.7H₂O, CAS RN 7782-85-6),trisodium phosphate (Na₃PO₄, CAS RN 7601-54-9), sodium phosphatetribasic dodecahydrate (Na₃PO₄.12H₂O, CAS RN 10101-89-0), sodiummetaphosphate (NaPO₃, CAS RN 10361-03-2), disodium pytophosphate(Na₂H₂P₂O₇, CAS RN 7758-16-9), tetrasodium pyrophosphate (Na₄O₇P₂, CASRN 7722-88-5), sodium trimetaphosphate (Na₃P₃O₉, CAS RN 7785-84-4),sodium tripolyphosphate (Na₅O₁₀P₃, CAS RN 13573-18-7), hexasodiumtetraphosphate (Na₆O₁₃P₄, CAS RN 14986-84-6) and sodiumpolymetaphosphate (CAS RN 50813-16-6).

Exemplary silicic acids and salts include sodium silicate (CAS RN15859-24-2), disodium metasilicate (CAS RN 6834-92-0), silicic acidsodium salt (CAS RN 1344-09-8), potassium silicate (CAS RN 1312-76-1),lithium silicate (CAS RN 10102-24-6), magnesium silicate and ammoniumsilicate.

Carboxylic acids, phosphoric acids, alkylsulfonic acids and arylsulfonicacids are preferred, as are sodium and ammonium salts of acids. Acidsand salts having low toxicity and low or moderate tendency to irritatethe skin are also preferred. Citric acid, phosphoric acid and theircorresponding sodium and ammonium salts are especially preferred.

The disclosed coating compositions may for example contain about 1 toabout 40 wt. %, about 5 to about 30 wt. % or about 7 to about 20 wt. %acid, anhydride or salt. When an acid and salt which buffer the coatingcomposition are employed, the amounts and types of acid and salt may forexample provide a pH of about 5 to about 9 or about 6 to about 8.

The disclosed coating compositions may contain a variety of adjuvantswhich will be familiar to persons having ordinary skill in the art orwhich can be determined using standard methods. For example, the coatingcompositions may contain one or more optional coalescents to facilitatefilm formation. Exemplary coalescents include fugitive coalescentsincluding glycol ethers such as EASTMAN™ EP, EASTMAN DM, EASTMAN DE,EASTMAN DP, EASTMAN DB and EASTMAN PM from Eastman Chemical Co. andester alcohols such as TEXANOL™ ester alcohol from Eastman Chemical Co.,and permanent coalescents including EPS™ 9147 low VOC coalescent fromEPS-Materials. Preferably, the optional coalescent is a low VOCcoalescent such as is described in U.S. Pat. No. 6,762,230 B2. Thecoating compositions preferably include a low VOC coalescent in anamount of at least about 0.5 weight %, more preferably at least about 1weight %, and yet more preferably at least about 2 weight %. The coatingcompositions also preferably include a low VOC coalescent in an amountof less than about 10 weight %, more preferably less than about 6 weight%, and yet more preferably less than about 4 weight %, based on thelatex polymer weight.

The disclosed coating compositions may include a surface-active agent(surfactant) that modifies the interaction of the coating compositionwith the substrate or with a prior applied coating. The surface-activeagent affects qualities of the composition including how the compositionis handled, how it spreads across the surface of the substrate, and howit bonds to the substrate. In particular, the agent can modify theability of the composition to wet a substrate. Surface-active agents mayalso provide leveling, defoaming or flow control properties, and thelike. If used, the surface-active agent is preferably present in anamount of less than 5 weight %, based on the total coating compositionweight. Exemplary surface-active agents include those available underthe trade designations STRODEX™ KK-95H, STRODEX PLF100, STRODEX PKOVOC,STRODEX LFK70, STRODEX SEK50D and DEXTROL™ 0050 from Dexter ChemicalL.L.C. of Bronx, N.Y.; HYDROPALAT™ 100, HYDROPALAT 140, HYDROPALAT 44,HYDROPALAT 5040 and HYDROPALAT 3204 from Cognis Corp. of Cincinnati,Ohio; LIPOLIN™ A, DISPERS™ 660C, DISPERS 715W and DISPERS 750W fromDegussa Corp. of Parsippany, N.J.; BYK™ 156, BYK 2001 and ANTI-TERRA™207 from Byk Chemie of Wallingford, Conn.; DISPEX™ A40, DISPEX N40,DISPEX R50, DISPEX G40, DISPEX GA40, EFKA™ 1500, EFKA 1501, EFKA 1502,EFKA 1503, EFKA 3034, EFKA 3522, EFKA 3580, EFKA 3772, EFKA 4500, EFKA4510, EFKA 4520, EFKA 4530, EFKA 4540, EFKA 4550, EFKA 4560, EFKA 4570,EFKA 6220, EFKA 6225, EFKA 6230 and EFKA 6525 from Ciba SpecialtyChemicals of Tarrytown, N.Y.; SURFYNOL™ CT-111, SURFYNOL CT-121,SURFYNOL CT-131, SURFYNOL CT-211, SURFYNOL CT 231, SURFYNOL CT-136,SURFYNOL CT-151, SURFYNOL CT-171, SURFYNOL CT-234, CARBOWET™ DC-01,SURFYNOL 104, SURFYNOL PSA-336, SURFYNOL 420, SURFYNOL 440, ENVIROGEM™AD-01 and ENVIROGEM AE01 from Air Products & Chemicals, Inc. ofAllentown, Pa.; TAMOL™ 1124, TAMOL 850, TAMOL 681, TAMOL 731 and TAMOLSG-1 from Rohm and Haas Co. of Philadelphia, Pa.; IGEPAL™ CO-210, IGEPALCO-430, IGEPAL CO-630, IGEPAL CO-730, and IGEPAL CO-890 from Rhodia Inc.of Cranbury, N.J.; T-DETT™ and T-MULZT™ products from Harcros ChemicalsInc. of Kansas City, Kans.; polydimethylsiloxane surface-active agents(such as those available under the trade designations SILWET™ L-760 andSILWET L-7622 from OSI Specialties, South Charleston, W. Va., or BYK 306from Byk Chemie) and fluorinated surface-active agents (such as thatcommercially available as FLUORAD FC-430 from 3M Co., St. Paul, Minn.).The surface-active agent may be a defoamer. Exemplary defoamers includeBYK 018, BYK 019, BYK 020, BYK 022, BYK 025, BYK 032, BYK 033, BYK 034,BYK 038, BYK 040, BYK 051, BYK 060, BYK 070, BYK 077 and BYK 500 fromByk Chemie; SURFYNOL DF-695, SURFYNOL DF-75, SURFYNOL DF-62, SURFYNOLDF-40 and SURFYNOL DF-110D from Air Products & Chemicals, Inc.; DEEFO™3010A, DEEFO 2020E/50, DEEFO 215, DEEFO 806-102 and AGITAN™ 31BP fromMunzing Chemie GmbH of Heilbronn, Germany; EFKA 2526, EFKA 2527 and EFKA2550 from Ciba Specialty Chemicals; FOAMAX™ 8050, FOAMAX 1488, FOAMAX7447, FOAMAX 800, FOAMAX 1495 and FOAMAX 810 from Degussa Corp.;FOAMASTER™ 714, FOAMASTER A410, FOAMASTER 111, FOAMASTER 333, FOAMASTER306, FOAMASTER SA-3, FOAMASTER AP, DEHYDRAN™ 1620, DEHYDRAN 1923 andDEHYDRAN 671 from Cognis Corp.

Exemplary coating compositions may contain one or more optionalpigments. Pigments suitable for use in the coating compositions will beknown to persons having ordinary skill in the art or can be determinedusing standard methods. Exemplary pigments include titanium dioxidewhite, carbon black, lampblack, black iron oxide, red iron oxide, yellowiron oxide, brown iron oxide (a blend of red and yellow oxide withblack), phthalocyanine green, phthalocyanine blue, organic reds (such asnaphthol red, quinacridone red and toluidine red), quinacridone magenta,quinacridone violet, DNA orange, or organic yellows (such as Hansayellow). The composition can also include a gloss control additive or anoptical brightener, such as that commercially available under the tradedesignation UVITEX™ OB from Ciba-Geigy.

In certain embodiments it is advantageous to include fillers or inertingredients in the coating composition. Fillers or inert ingredientsextend, lower the cost of, alter the appearance of, or provide desirablecharacteristics to the composition before and after curing. Exemplaryfillers or inert ingredients include, for example, clay, glass beads,calcium carbonate, talc, silicas, feldspar, mica, barytes, ceramicmicrospheres, calcium metasilicates, organic fillers, and the like. Forexample, the composition may include abrasion resistance promotingadjuvants such as silica or aluminum oxide (e.g., sol gel processedaluminum oxide). Suitable fillers or inert ingredients are preferablypresent in an amount of less than 15 weight %, based on the totalcoating composition weight.

The disclosed coating compositions may include wax emulsions to improvecoating physical performance or rheology control agents to improveapplication properties. Exemplary wax emulsions include MICHEM™Emulsions 32535, 21030, 61335, 80939M and 7173MOD from Michelman, Inc.of Cincinnati, Ohio and CHEMCOR™ 20N35, 43A40, 950C25 and 10N30 fromChemCor of Chester, N.Y. Exemplary rheology control agents includeRHEOVIS™ 112, RHEOVIS 132, RHEOVIS 152, VISCALEX™ HV30, VISCALEX AT88,EFKA 6220 and EFKA 6225 from Ciba Specialty Chemicals; BYK 420 and BYK425 from Byk Chemie; RHEOLATE™ 205, RHEOLATE 420 and RHEOLATE 1 fromElementis Specialties of Hightstown, N.J.; ACRYSOL™ L TT-615, ACRYSOLRM-5, ACRYSOL RM-6, ACRYSOL RM-8W, ACRYSOL RM-2020 and ACRYSOL RM-825from Rohm and Haas Co.; NATROSOL™ 250LR from Hercules Inc. ofWilmington, Del. and CELLOSIZE™ QP09L from Dow Chemical Co. of Midland,Mich.

The disclosed coating compositions may include a biocide, fungicide,mildewcide or other preservative. Inclusion of such materials isespecially desirable due to the very good water resistance properties ofthe disclosed coating compositions and the consequent likelihood thatthey will be selected for use in abnormally damp or wet conditions oreven under standing or moving water. Exemplary such preservativesinclude KATHON™ LX microbicide, ROZONE™ 2000 fungicide and ROCIMA™ 80algicide from Rohm & Haas of Philadelphia, Pa., the BUSAN™ series ofbactericides, fungicides and preservatives including BUSAN 1292 and 1440from Buckman Laboratories of Memphis, Tenn.; the POLYPHASE™ series ofbactericides, fungicides and algaecides including POLYPHASE™ 663 and 678from Troy Chemical Corp. of Florham Park, N.J., the IRGAROL™ andNUOSEPT™ series of biocides including NUOSEPT 91, 101, 145, 166, 485,495, 497, 498, 515, 635W and 695 from International SpecialtiesProducts, the FUNGITROLT™ series of fungicides including FUNGITROL C,334, 404D, 720, 920, 940, 960, 2002, and 2010 from InternationalSpecialties Products, and the DOWICIL™ series of antimicrobials andpreservatives including DOWICIL 75, 96, 150, 200, and QC-20 from DowChemical Co.

The coating composition may also include other adjuvants which modifyproperties of the coating composition as it is stored, handled, orapplied, and at other or subsequent stages. Desirable perfoiniancecharacteristics include chemical resistance, abrasion resistance,hardness, gloss, reflectivity, appearance, or combinations of thesecharacteristics, and other similar characteristics. Many suitableadjuvants are described in Koleske et al., Paint and Coatings Industry,April, 2003, pages 12-86 or will be familiar to those skilled in theart. Representative adjuvants include amines, anti-cratering agents,colorants, curing indicators, dispersants, dyes, flatting agents (e.g.,BYK CERAFLOUR™ 920 from Byk Chemie), glycols, heat stabilizers, levelingagents, mar and abrasion additives, optical brighteners, plasticizers,sedimentation inhibitors, thickeners, ultraviolet-light absorbers andthe like to modify properties.

The disclosed coating compositions preferably have a minimum filmforming temperature (MFFT) about 0 to about 55° C., more preferablyabout 0 to about 20° C., when tested with a Rhopoint 1212/42, MFFTBar-60, available from Rhopoint Instruments Ltd. of East Sussex, UnitedKingdom. The compositions preferably have a PVC of less than about 50percent, more preferably less than about 35 percent, and most preferablyless than about 25 percent. The compositions preferably include lessthan 10 weight %, more preferably less than 7 weight %, and mostpreferably less than 4 weight % total VOCs based upon the totalcomposition weight.

The coating composition may be applied directly to the substrate orapplied to a substrate which has been optionally subjected to one ormore of pretreatment with a water-soluble acid, acid anhydride or acidsalt like those described above, coating with a sealer, or coating witha primer. Any suitable application method may be used for suchpretreatment, sealer or primer. For example, the pretreatment may beapplied to a wet or dry substrate. When applied at a manufacturinglocation, the pretreatment may be applied before or after or both beforeand after the substrate is subjected to drying (e.g., oven drying) toremove water from the binder. Normally it will be most convenient toapply the pretreatment after the substrate has been formed into adesired shape (e.g., a board) and before the substrate is dried toremove water from the binder, as the drying step will also remove waterfrom the pretreatment solution. The pretreatment may be applied usingany convenient method including brushing (e.g., using a brush coater),direct roll coating, reverse roll coating, flood coating, vacuumcoating, curtain coating and spraying. The various techniques each offera unique set of advantages and disadvantages depending upon thesubstrate profile, morphology and tolerable application efficiencies.The pretreatment may be applied only to burnished regions and at leastone edge proximate the burnished region (e.g., over the burnished regionand about 100, 50 or 25 mm beyond that region past an edge and into anunburnished area); to all edges, sides and ends of the substrate; or toall edges, sides and ends and to at least one and if desired both majorface(s) of the substrate. The concentration of acid, acid anhydride oracid salt in the pretreatment solution may vary, and may be determinedor adjusted empirically using the Wet Adhesion test described below.There may be an optimal concentration range below and above whichreduced topcoat adhesion may be observed. For example, concentrations ofabout 1 to about 86, about 2 to about 75, about 5 to about 60, about 8to about 40, or about 10 to about 30 wt. % acid, acid anhydride or acidsalt in water may be employed, based on the total weight of thesolution. In one embodiment, the amount of acid, acid anhydride or acidsalt in the pretreatment solution is from about 1 to about 30 weight %based on the total weight of the solution.

The optional sealer or primer and the disclosed coating composition maybe roll coated, sprayed, curtain coated, vacuum coated, brushed, orflood coated using an air knife system. For field applied coatingsystems, e.g., cement garage floors, floor tiles, decks, and the like,the optional sealer or primer and the disclosed coating compositiondesirably are applied by rolling, spraying, or brushing. Forfactory-applied applications, preferred application methods provide auniform coating thickness and are cost efficient. Especially preferredapplication methods employ factory equipment which moves a substratewith a first major surface past a coating head and thence past suitabledrying or curing equipment. The applied materials desirably cover atleast a portion of the first major surface of the substrate, andpreferably cover the entire first major surface, in a substantiallyuniformly thick layer. Accordingly, the disclosed coated articlespreferably are coated on at least one major surface with the coatingcomposition. More preferably, the coated articles are coated on a majorsurface and up to four minor surfaces including any edges. Mostpreferably, the coated articles are coated on all (e.g., both) majorsurfaces, and up to four minor surfaces including any edges.

Crush Resistance

Preferred coatings resist crush damage. Coated products (e.g., fibercement siding products) may be evaluated using a Visual Assessment ofCrush Resistance test as described in U.S. Patent Application No.2007/0110981, published May 17, 2007 and the 1 to 5 rating scale shownbelow in Table 1, with 5 being essentially no damage and 1 being severecoating damage:

TABLE 1 Visual Assessment Rating value Panel Appearance 1 Obviouslycrushed: Peaks are severely crushed and the grain pattern from theopposing board is embossed into the coating, causing severe wrinkling ofthe coating around the damaged area. 2 Moderately crushed: Peaks showflattening to widths over 4 mm, and the grain pattern from the opposingboard is slightly embossed into the coating 3 Slightly crushed: Manypeaks show flattening to a width of 2 mm to 4 mm. 4 Very slightlycrushed: A few peaks show peak flattening to a width less than 2 mm. 5Uncrushed: no crushed peaks or glossy spots are visible to the unaidedeye or with 5X magnification.

The disclosed coatings preferably provide crush resistance of at least3, more preferably at least 4 and most preferably 5 when twoface-to-face coated embossed substrates are subjected to a pressure ofabout 6 kg/cm², more preferably about 8 kg/cm², and most preferablyabout 10 kg/cm². For example, the test board samples preferably achievea rating of 3 or greater, more preferably 4 or greater, and optimally 5,when tested at a pressure of about 8 kg/cm².

Hot Tire Test Procedure

Preferred coatings also resist damage from hot tires. Coating substrates(e.g., coated cementitious substrates) may be evaluated by a visualassessment of hot tire pick up resistance as follows. Over a 6″×6″(15.24×15.24 cm) pre-cast concrete block the coating composition isapplied at an application rate of 300 sq. ft./gal. (6.13 square metersper liter), with a minimum coated area of 3″×6″ (7.62×15.24 cm) toaccommodate an automobile tire section. After curing 4 hours, a secondcoat is applied. The coating is allowed to cure for 7 days at 20-25° C.,and 35%-50% R.H. An automobile tire section, measuring approximately6″×3″ (15.24×7.62 cm), with wear approximating 6,000 to 10,000 miles(9660 to 16,090 km) is used in the test. A forced-convection laboratoryoven is pre-heated to 140° F. (+/−2° F.) (60° C.) prior to placing thesample and tire sections into the oven for heated storage. After thecoating has cured for 7 days, the test sample is submerged in water at20-25° C. for 16 hours prior to initiating the test. After removing thetest sample from the water bath, a wet cloth or towel is wrapped aroundthe test sample, making sure it contacts the coating, and is placed inthe pre-heated oven. The tire section to be used is placed in the ovenalso, though not on top of the sample at this point. Periodically, thecloth/towel is misted with water to maintain the moisture level. Thetest sample and tire section are allowed to remain in the oven for 1hour. After 1 hour, the test sample and tire section are removed fromthe oven, and the cloth/towel is removed from the test sample. The testsample is placed on the lower plate of a laboratory press, with thecoating facing up, and then the tire section is placed on top of thesample, centering the tire tread on the coated area of the sample. Usinga contact area of 3″×6″ (7.62×15.24 cm), a force of 2700 lbs. (1,224 kg)should be applied, generating 150 psi (1,034 kPa). This is intended tosimulate the effect of a 5000 lb. (2,267 kg) vehicle driven onto thecoated surface. The test sample and tire section is allowed to remain inthe press for 1 hour. The press should be checked periodically to insurethat the force applied remains constant. After 1 hour, the tire sectionand test sample are removed and evaluated. Observations are made as towhether any of the coating has delaminated from the surface. The coatingis further examined and any marring, adhesion loss, or any latentprints/images left behind by the tire section are noted. In some cases,an image or print of the tire section may be left behind, but may not bereadily visible unless the sample is tilted or observed at an angle. Oneportion of the coating should be cleaned with a commercial householdcleaning product such as Formula 409™ cleaner from The Clorox Company,and it should be noted whether the cleaner has removed any prints orimages that existed on the coating, and whether the cleaner stained thecoating. The coating should exhibit no declamation, marring, imprintingor other scuffing that cannot be removed by light cleaning with thehousehold cleaner. Desirably, a composition employing the silaneexhibits improved delamination resistance in this test compared to acomposition that does not contain the silane.

Wet Adhesion and Early Water Resistance

Wet Adhesion and Early Water Resistance may be evaluated using amodified version of ASTM D3359-02, “Standard Test Methods for MeasuringAdhesion by Tape Test”, carried out as follows. Two coats of the coatingcomposition are applied 4 hours apart at a dry film thickness of 0.02 mmto a Black Carrara Glass panel and allowed to dry for a further fourhours at ambient temperature. The coated panels are partially immersedin a water bath for a period of 16-18 hours. Immediately following theimmersion period, the paint films are evaluated for wet and dry adhesionusing ASTM D3359, Test Method B. “Wet Adhesion” and “Dry Adhesion”performance are rated on a 0 to 5 scale, with 0 representing greaterthan 65% coating removal and 5 representing 0% coating removal, and theWet Adhesion results typically being of greatest interest. A visualinspection and subjective ratings of blister resistance and blushresistance for immersed panels are also used to evaluate Early WaterResistance. Desirably, a composition employing the silane exhibits animprovement in one or more of wet adhesion, dry adhesion, blisterresistance or blush resistance in these tests compared to a compositionthat does not contain the silane.

Pull-Off Strength

Pull-Off Strength may be evaluated using ASTM D 4541-93, “Standard TestMethod for Pull-Off Strength of Coatings Using Portable AdhesionTesters”, carried out as follows. Coatings were applied to 30 cm×60 cmprecast concrete blocks using brush coating and a 0.08 mm wet coatingthickness. The coating was allowed to cure 4 hours followed by brushcoat application of a second 0.08 mm wet coating. The finished coatingwas then allowed to cure at room temperature (about 25° C.) for 7 daysbefore performing adhesion testing. Adhesion tests were run intriplicate, using three applied 20 mm diameter pull-off buttons(“dollies”) per coating sample. LOCTITE™ two-part marine epoxy fromHenkel Corporation and a 50 minute cure time were employed to adhere thedollies to the coatings. An ELCOMETER™ Model 106 Portable AdhesionTester from Elcometer Inc. was used to measure pull-off forces.

The following examples are offered to aid in understanding of thepresent invention and are not to be construed as limiting the scopethereof. Unless otherwise indicated, all parts and percentages are byweight. The Tg inflection points were determined using a Q SERIES™ DSCthermal analysis instrument from TA Instruments of New Castle, Del.

EXAMPLES Example 1 Multistage Latex Polymer

An exemplary multistage silane-functional acetoacetyl-functional latexpolymer may be prepared as follows. A reactor is charged with 500-800parts of deionized water and 2-6 parts emulsifier. The reaction mixtureis heated to 75°-80° C. under a nitrogen blanket. During heating,pre-emulsion 1 is formed having 75-250 parts of deionized water, 2-9parts of emulsifier, 0.2-0.6 parts persulfate initiator, 50-150 parts ofbutyl acrylate, 0-200 parts of methylmethacrylate, 250-450 parts ofbutyl methacrylate, 0-40 parts of AAEM, 0-15 parts vinyl silane, and5-30 parts of (meth)acrylic acid. In a separate vessel, pre-emulsion 2is formed having 75-250 parts of deionized water, 2-9 parts ofemulsifier, 0.2-0.6 parts persulfate initiator (e.g., sodiumpersulfate), 150-500 parts of methylmethacrylate, 5-100 parts of butylacrylate, 0-40 parts of AAEM, 0-15 parts vinyl silane, and 5-30 parts of(meth)acrylic acid. After the reaction mixture reaches 75° C., 1-6 partsof persulfate initiator is added to the reactor and the pre-emulsion 1is added over a 1-3 hour feed rate. After pre-emulsion 1 is added, thecontainer is rinsed with 20 parts deionized water and pre-emulsion 2 isadded over a 1-3 hour feed rate. The reaction temperature is heldbetween 80° C. and 85° C. during polymerization. After the pre-emulsion2 feed is complete, the container is rinsed with 20 parts of deionizedwater and the reaction is held 30 minutes. Post-reaction addition of0.5-1.5 parts t-butyl hydroperoxide mixed with 20 parts of deionizedwater and 0.3-1.5 parts of isoascorbic acid mixed with 20 parts ofdeionized water are then added over 30 minutes. The resulting latexpolymer is then cooled to 40° C., and 28% ammonia is added to adjust thepH to 7.5-8.5.

Example 2 Multistage Latex Polymer and Epoxy-Functional Silane

Using the method of Example 1 (but without employing vinyl silane in thelatex reaction mixture), a multistage latex polymer was prepared from afirst monomer mixture containing butyl acrylate, methyl methacrylate,butyl methacrylate, AAEM, acrylic acid and methacrylic acid and a secondmonomer mixture containing butyl acrylate, methyl methacrylate, AAEM andacrylic acid. Five parts AAEM were employed per 100 parts total monomer.100 Parts of the multistage latex polymer were then combined with 0.8parts SILQUEST™ A-187 γ-glycidoxypropyltriethoxysilane. FIG. 4 shows theDSC curve, and demonstrates that the polymer exhibited two distinct Tgvalues, namely a soft stage Tg at about 8.6° C. and a hard stage Tg atabout 89.3° C. Solids were 40% and the MMFT was less than 10° C.

Example 3 Vinyl Silane-Containing Multistage Latex Polymer

Using the method of Example 1, a vinyl silane-functional multistagelatex polymer was prepared from a first monomer mixture containing butylacrylate, methyl methacrylate, butyl methacrylate, AAEM, SILQUEST A-171vinyl silane, acrylic acid and methacrylic acid and a second monomermixture containing methyl methacrylate, butyl acrylate, AAEM, A-171vinyl silane and acrylic acid. Five parts AAEM and 0.8 parts vinylsilane were employed per 100 parts total monomer. FIG. 5 shows the DSCcurve, and demonstrates that the polymer exhibited two distinct Tgvalues, namely a soft stage Tg at about 7.2° C. and a hard stage Tg atabout 92.5° C. Solids were 40% and the MMFT was less than 10° C.

Example 4 Multistage Latex Polymer and Amino-Functional silane

In a method like that of Example 2, the Example 2 multistage latexpolymer may be combined with 0.8 parts aminopropyltriethoxysilane ratherthan 0.8 parts γ-glycidoxypropyltriethoxysilane. Theaminopropyltriethoxysilane would react at room temperature with theacetoacetyl functionality in the multistage latex polymer.

Example 5 Epoxy Silane-Containing Multistage Latex Polymer

In a method like that of Example 3, an epoxy silane-functionalmultistage latex polymer may be prepared from first and second monomermixtures containing γ-glycidoxypropyltriethoxysilane rather than A-171vinyl silane.

Example 6 Base Coating Resin

An exemplary base coating resin may be prepared as follows. In a mixingvessel equipped with a high-speed mixer and mixing blade mixer arecharged 10 to 50 parts water, 40 to 85 parts of a silane-containingmultistage latex polymer solution and 1 to 40 parts water-soluble acid,acid anhydride or acid salt. If desired, 0 to 20 parts other non-pigmentadditives may be introduced. If desired (for example, to make apigmented coating rather than a clearcoat), up to about 50 parts ofpigments or flatting agents may be introduced.

Examples 7a through 7d

To demonstrate the effects of using a multistage latex polymer andsilane when a water-soluble acid, acid anhydride or acid salt is notpresent, a series of four coating compositions was prepared usingmodified versions of the Example 3 polymer. The first composition(Example 7a) employed a silane-free multistage latex polymer formed asin Example 3 but without employing vinyl silane in the latex reactionmixture. The second composition (Example 7b) employed a silane-freesingle stage latex polymer formed from the monomers methyl methacrylate,butyl methacrylate, butyl acrylate, acetoacetoxyethylmethacrylate andacrylic acid and having a calculated 15° C. Tg. The third composition(Example 7c) employed a silane-containing multistage latex polymer madeusing A-187 epoxy-functional silane rather than A-171 vinyl silane inthe Example 3 latex reaction mixture. The fourth composition (Example7d) employed the Example 3 multistage latex polymer. The coatingcompositions also included water, SURFYNOL™ PSA-336 wetting agent fromAir Products and Chemicals, Inc., BYK™-024 defoamer from Altana AG,TEXANOL™ ester alcohol coalescent from Eastman Chemical Company, 28%ammonium hydroxide from Sigma-Aldrich Co., FUNGITROL™ 940 fungicide fromInternational Specialties Products, NUOSEPT™ 485 biocide (8.5%1,2-Benzisothiazol-3(2H)-one) from International Specialties Products,and ethylene glycol from Sigma-Aldrich Co. as shown below in Table 2.The ingredients were mixed for about 30 minutes using moderate agitationuntil a well-dispersed, homogenous mixture was formed. The compositionswere evaluated to determine film appearance, blush resistance forimmersed samples, and Wet Adhesion using ASTM D3359, Test Method B. Theresults are shown below in Table 3:

TABLE 2 Example Example Example Example Ingredient 7a 7b 7c 7d Water 183183 183 183 Silane-free multistage 645 latex polymer Silane-free single645 stage latex polymer Silane-containing 645 multistage latex polymer(A-187) Silane-containing 645 multistage latex polymer (A-171) SURFYNOLPSA-336 3 3 3 3 wetting agent BYK-024 defoamer 3 3 3 3 TEXANOL esteralcohol 15 15 15 15 coalescent Ammonium hydroxide 3 3 3 3 (28%)FUNGITROL 940 8 8 8 8 fungicide NUOSEPT 485 biocide 5 5 5 5 Ethyleneglycol 9.3 9.3 9.3 9.3

TABLE 3 Example Example Example Example 7a 7b 7c 7d Film appearance Filmfilled Smooth Smooth, Smooth, with Film defect-free defect-free bubblesand film film blisters Blush resistance No blushing Heavy No blushing Noblushing blushing Wet Adhesion 0 0 5 5

The results in Tables 2 and 3 show that use of a multistage latex andsilane provide a desirable combination of very good film appearance,blush resistance and Wet Adhesion.

Examples 8a and 8b Coating Compositions

Using the method of Example 6, coating compositions were prepared bycombining the ingredients shown below in Table 4 and mixing for about 30minutes using moderate agitation until a well-dispersed, homogenousmixture was formed:

TABLE 4 Example Example Ingredient 8a 8b Water 183 183 Example 5 baselatex 645 645 Ammonium citrate 153 Ammonium phosphate 153 SURFYNOLPSA-336 wetting agent 3 3 BYK-024 defoamer 3 3 TEXANOL ester alcoholcoalescent 15 15 Ammonium hydroxide (28%) 3 3 Ethylene glycol 9.3 9.3

The Example 8a and 8b compositions provide clear sealers with goodhardness, good Early Water Resistance and good adhesion to cement,especially to cement edges and corners. If the multistage latex polymeris replaced by a single stage polymer (e.g., like that used in Example7b), the coatings will have reduced hardness, reduced Early WaterResistance and reduced adhesion to cement. If silane is not employed,the coatings will have reduced Wet Adhesion and reduced Early WaterResistance. If the acid or salt is not employed, the coatings will havereduced adhesion to cement and especially to cement edges and corners.

Examples 9a through 9d

Clear concrete sealer formulations containing 10 wt. % or 20 wt. %sodium or ammonium citrate were prepared by combining the ingredientsshown below in Table 6 other than the latex, measuring pH and adjustingif need be to obtain an alkaline mixture, adding the latex and mixingfor about 30 minutes using moderate agitation until a well-dispersed,homogenous mixture was formed. The compositions were evaluated todetermine Pull-Off Strength. The ingredients and results are shown belowin Table 5:

TABLE 5 Example Example Example Example Ingredient 9a 9b 9c 9d Water 183183 183 183 Sodium citrate 96 215 Ammonium citrate 96 215 SURFYNOLPSA-336 3 3 3 3 wetting agent BYK-024 defoamer 3 3 3 3 TEXANOL esteralcohol 15 15 15 15 coalescent Ammonium hydroxide 3 3 3 3 (28%) Ethyleneglycol 9.3 9.3 9.3 9.3 Example 2 latex 645 645 645 645 pH prior to baselatex 8.16 8.16 5.28 5.28 addition pH after alkalinity 7.25 7.25adjustment Pull-Off Strength, 2.53 3.33 2.99 3.10 MPa Standarddeviation, 0.65 0.59 0.33 1.23 MPA Observation 1 of 3 2 of 3 showedshowed concrete concrete pull-out pull-out

The results in Table 5 show excellent concrete adhesion. In Example 9b,1 of the 3 tested compositions exhibited concrete pull-out under theELCOMETER dolly, and in Example 9d, 2 of the 3 samples exhibitedconcrete pull-out. When the salt was omitted, the average Pull-OffStrength was 2.30 Mpa with a standard deviation of 0.29 Mpa and noconcrete-pull-out was observed.

Examples 10a through 10d

Using the method of Examples 9a through 9d, clear concrete sealerformulations containing 10 wt. % or 20 wt. % sodium or ammoniumphosphate were prepared. The ingredients and results are shown below inTable 6:

TABLE 6 Example Example Example Example Ingredient 10a 10b 10c 10d Water183 183 183 183 Sodium phosphate 96 215 Ammonium phosphate 96 215SURFYNOL PSA-336 3 3 3 3 wetting agent BYK-024 defoamer 3 3 3 3 TEXANOLester alcohol 15 15 15 15 coalescent Ammonium hydroxide 3 3 3 3 (28%)Ethylene glycol 9.3 9.3 9.3 9.3 Example 2 latex 645 645 645 645 pH priorto base latex 9.13 9.13 8.60 8.60 addition Pull-Off Strength, 3.91 3.103.56 3.45 MPa Standard deviation, 1.30 0.56 1.14 0.49 MPA Observation 1of 3 1 of 3 showed showed concrete concrete pull-out pull-out

The results in Table 6 show excellent concrete adhesion.

Examples 11a through 11d

The method of Examples 9a through 9d was repeated using the Example 3latex. The ingredients and results are shown below in Table 7:

TABLE 7 Example Example Example Example Ingredient 11a 11b 11c 11d Water183 183 183 183 Sodium citrate 96 215 Ammonium citrate 96 215 SURFYNOLPSA-336 3 3 3 3 wetting agent BYK-024 defoamer 3 3 3 3 TEXANOL esteralcohol 15 15 15 15 coalescent Ammonium hydroxide 3 3 3 3 (28%) Ethyleneglycol 9.3 9.3 9.3 9.3 Example 3 latex 645 645 645 645 pH prior to latex8.16 8.16 5.28 5.28 addition pH after alkalinity 7.25 7.25 adjustmentPull-Off Strength, 3.10 2.18 2.07 2.99 MPa Standard deviation, 0.28 0.430.57 0.33 MPA Observation 2 of 3 showed concrete pull-out

The results in Table 7 show good concrete adhesion for each salt at oneof the tested amounts, and with concrete pull-out for 2 of the 3 samplesin Example 11a. In some instances the salt-containing compositionsexhibited a viscosity increase a few days after mixing. When the saltwas omitted, the average Pull-Off Strength was 2.76 Mpa with a standarddeviation of 0.56 Mpa and no concrete pull-out was observed. The amountsand pH values in Examples 11a through 11d had not been optimized, butwith such optimization the viscosity stability or concrete adhesionresults might further improved.

Examples 12a through 12d

The method of Examples 10a through 10d was repeated using the Example 3latex. The ingredients and results are shown below in Table 8:

TABLE 8 Example Example Example Example Ingredient 12a 12b 12c 12d Water183 183 183 183 Sodium phosphate 96 215 Ammonium phosphate 96 215SURFYNOL PSA-336 3 3 3 3 wetting agent BYK-024 defoamer 3 3 3 3 TEXANOLester alcohol 15 15 15 15 coalescent Ammonium hydroxide 3 3 3 3 (28%)Ethylene glycol 9.3 9.3 9.3 9.3 Example 3 latex 645 645 645 645 pH priorto base latex 9.13 9.13 8.60 8.60 addition Pull-Off Strength, 2.87 2.413.33 3.56 MPa Standard deviation, 1.17 0.28 0.43 0.16 MPA Observation 1of 3 1 of 3 3 of 3 showed showed showed concrete concrete concretepull-out pull-out pull-out

The results in Table 8 show excellent concrete adhesion.

Example 13

Using the method of Examples 9a through 9d, a clear concrete sealerformulation containing 20 wt. % potassium silicate was prepared. Theingredients and results are shown below in Table 9:

TABLE 9 Example Ingredient 11 Water 183 Potassium silicate 215 SURFYNOLPSA-336 wetting agent 3 BYK-024 defoamer 3 TEXANOL ester alcoholcoalescent 15 Ammonium hydroxide (28%) 3 Ethylene glycol 9.3 Example 5base latex 645 pH prior to base latex addition 11.43 Pull-Off Strength,MPa 3.33 Standard deviation, MPA 1.55

The results in Table 9 show excellent concrete adhesion.

Example 14

A gray concrete floor paint formulation may be prepared by combining theingredients shown below in Table 10 and mixing for about 30 minutesusing moderate agitation until a well-dispersed, homogenous mixture isformed. The acid or salt may for example be citric acid, phosphoric acidor their corresponding sodium or ammonium salts:

TABLE 10 Ingredient Supplier Parts Water 42 Acid or salt 100 TAMOL ™731N dispersant Rohm and Haas Co. 7 TRITON ™ CF-10 surfactant DowChemical Co. 3 DREWPLUS ™ L-475 foam control Ashland Aqualon 1 agentFunctional Ingredients TI-PURE ™ R902 titanium dioxide E. I. DuPont de75 Nemours and Co. MINEX ™ 7 nepheline syenite Unimin Canada Ltd. 150ATTAGEL ™ 50 attapulgite BASF SE 2 Example 6 base latex 552.5 NUOSEPT485 biocide International 5 Specialties Products Ammonium hydroxide(28%) Sigma-Aldrich Co. 1 Ethylene glycol Sigma-Aldrich Co. 9.33 Water120.8 EPS ™ 9147 low VOC coalescent EPS-Materials 22 DREWPLUS L-475 foamcontrol 2 agent ACRYSOL ™ RM-25 non-ionic Rohm and Haas Co. 2 urethanerheology modifier ACRYSOL RM-2020 non-ionic Rohm and Haas Co. 8 urethanerheology modifier TINT-EZE ™ 2491 lamp black Color Corporation 8colorant of America TINE-EZE 2475 yellow iron oxide Color Corporation 5colorant of America

As mentioned above, the invention provides a method for preparing acoated article, which method comprises providing a cementitioussubstrate, coating at least a portion of the substrate with an aqueouscoating composition comprising a multistage latex polymer; silane; and awater-soluble acid, acid anhydride or acid salt, and allowing thecoating composition to harden. The invention also provides a coatedarticle comprising a cementitious substrate having at least one majorsurface on which is coated a layer comprising an aqueous coatingcomposition comprising a multistage latex polymer; silane; and awater-soluble acid, acid anhydride or acid salt. Other embodiments ofthe invention include a method or coated article wherein:

-   -   the multistage latex polymer comprises at least one soft stage        having a Tg between about −65 and 30° C. and at least one hard        stage having a Tg between about 30 and 230° C.; or    -   the multistage latex polymer comprises 50 to 90 weight % soft        stage polymer morphology having a Tg between about −5 and 25° C.        and 10 to 50 weight % hard stage polymer morphology having a Tg        between about 30 and 105° C., based on total polymer weight; or    -   the composition contains at least 10 weight % multistage latex        polymer, based on total solids of the composition; or    -   the multistage latex polymer has acetoacetoxy functionality; or    -   the multistage latex polymer is made using from 0.5 to 10 weight        % acetoacetoxy functional monomer based on the total weight of        the multistage latex polymer; or    -   the silane comprises an olefinic silane, allyl silane or        mercapto silane; or    -   the multistage latex polymer has silane functionality; or    -   the silane is not reacted with or reactive with the multistage        latex polymer; or    -   the silane is bis(triethoxysilylethane, 1,2        bis(trimethoxysilyl)decane, (trimethoxysilyl)ethane,        bis[(3-methyldimethoxysilyl)propyl]-polypropylene oxide,        carboxyethylsilanetriol sodium salt,        bis(2-hydroxyethyl)-3-aminopropyl-triethoxysilane,        triethoxysilylmethanol, N-(triethoxysilylpropyl)-o-polyethylene        oxide urethane, N-(3-triethoxysilylpropyl)gluconamide,        diethylphosphatoethyltriethoxysilane,        3-trihydroxysilylpropylmethylphosphonate sodium salt,        3-(trihydroxysilyl)1-1propane-sulfonic acid, triethoxysilyl        modified poly-1,2-butadiene or aminoalkyl silsesquioxane        oligomer; or    -   the silane is epoxy-functional or amino-functional; or    -   the silane has the formula:

R₁Si(R₂)_(3-n)(OR₃)_(n)

-   -   -   where n is 1, 2 or 3;        -   the R₁ group is alkyl, cycloalkyl, phenyl, cycloalkylalkyl,            alkenylcycloalkyl, alkenylphenyl, or phenylalkyl, wherein R₁            contains at least one functional group and can optionally            include a silane oligomer;        -   each R₂ group is independently hydrogen, alkyl, cycloalkyl,            phenyl, cycloalkylalkyl, alkenylcycloalkyl, alkenylphenyl,            phenylalkyl, or a silane oligomer, wherein each R₂ group can            optionally include OR₃ groups or a functional group; and        -   each R₃ group is independently hydrogen, alkyl, cycloalkyl,            phenyl, cycloalkylalkyl, alkenylcycloalkyl, alkenylphenyl,            or phenylalkyl; or

    -   the silane is β-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane,        γ-glycidoxypropyltrimethoxysilane,        γ-glycidoxypropylmethyldiethoxysilane,        γ-glycidoxypropyltriethoxysilane,        γ-glycidoxypropylmethyldimethoxysilane,        5,6-epoxyhexyltriethoxysilane, or a hydrolyzate or mixture        thereof; or

    -   the silane is trimethoxysilylpropyldiethylenetriamine,        N-methylaminopropyltrimethoxysilane,        aminoethylaminopropylmethyldimethoxysilane,        aminoethylaminopropyltrimethoxysilane,        aminopropylmethyldimethoxysilane, aminopropyltrimethoxysilane,        polymeric aminoalkylsilicone,        aminoethylaminoethylaminopropyl-trimethoxysilane,        aminopropylmethyldiethoxysilane, aminopropyltriethoxysilane,        4-aminobutyltriethoxysilane, oligomeric aminoalkylsilane,        m-aminophenyltrimethoxysilane,        phenylaminopropyltrimethoxysilane,        1,1,2,4-tetramethyl-1-sila-2-azacyclopentane,        aminoethylaminopropyltriethoxysilane,        aminoethylaminoisobutylmethyldimethoxysilane,        benzylethylenediaminepropyltrimethoxysilane, or a hydrolyzate or        mixture thereof; or

    -   the silane is a silane coupling agent; or

    -   the silane has an average molecular weight of from about 140 to        about 500 g/mole; or

    -   the silane is at least about 0.2% and less than about 10% of the        latex polymer weight; or

    -   the water-soluble acid or salt has a water solubility of at        least 5 wt. %; or

    -   the water-soluble acid or salt is completely water miscible; or

    -   the acid is inorganic; or

    -   the acid is organic; or

    -   the water-soluble acid or salt is a carboxylic, sulfonic,        phosphorus, nitric, nitrous; hydrogen halide or mineral acid or        salt thereof; or

    -   the composition contains a sodium, potassium or ammonium salt of        the water-soluble acid; or

    -   the composition contains a magnesium, calcium or iron salt of        the water-soluble acid; or

    -   the composition contains a mixture of water-soluble acid, acid        anhydride or salt which buffers the coating composition pH; or

    -   the composition contains about 1 to about 40 wt. % acid, acid        anhydride or salt; or

    -   the composition has a pH of about 5 to about 9; or

    -   the composition is alkaline.

All patents, patent applications and literature cited in thespecification are hereby incorporated by reference in their entirety. Inthe case of any inconsistencies, the present disclosure, including anydefinitions therein will prevail. The invention has been described withreference to various specific and preferred embodiments and techniques.However, it should be understood that many variations and modificationsmay be made while remaining within the invention.

Having thus described the preferred embodiments of the presentinvention, those of skill in the art will readily appreciate that theteachings found herein may be applied to yet other embodiments withinthe scope of the attached claims.

1. A coating composition, comprising a multistage latex polymer, silane,and a water-soluble acid, acid anhydride or acid salt capable of etchingor otherwise reacting with the surface of a cementitious substrate so asto provide improved coating adhesion.
 2. The composition of claim 1,wherein the multistage latex polymer comprises at least one soft stagehaving a Tg between about −65 and 30° C. and at least one hard stagehaving a Tg between about 30 and 230° C.
 3. The composition of claim 2,wherein the multistage latex polymer comprises 50 to 90 weight % softstage polymer morphology having a Tg between about −5 and 25° C. and 10to 50 weight % hard stage polymer morphology having a Tg between about30 and 105° C., based on total polymer weight.
 4. The composition ofclaim 1, wherein the composition contains at least 10 weight %multistage latex polymer, based on total solids of the composition. 5.The composition of claim 1, wherein the multistage latex polymer hasacetoacetoxy functionality.
 6. The composition of claim 5, wherein themultistage latex polymer is made using from 0.5 to 10 weight %acetoacetoxy functional monomer based on the total weight of themultistage latex polymer.
 7. The composition of claim 1, wherein thesilane comprises an olefinic silane, allyl silane or mercapto silane. 8.The composition of claim 1, wherein the multistage latex polymer hassilane functionality.
 9. The composition of claim 8, wherein the silaneis 3-acryloxypropyl trimethoxysilane,γ-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane,3-mercaptopropyltriethoxysilane,s-(octanoyl)mercaptopropyltriethoxysilane,3-thiocyanatopropyltriethoxysilane,3-mercaptopropylmethyldimethoxysilane,bis[3-(triethoxysilyl)propyl]-tetrasulfide,bis[3-(triethoxysilyl)propyl]-disulfide triethoxysilane,vinyltriacetoxysilane, vinyl trimethoxysilane, vinyltriethoxysilane,vinyl-tris-(2-methoxyethoxy)silane,γ-methacryloxypropyltrimethoxysilane, or vinyl methyldimethoxysilane.10. The composition of claim 1, wherein the silane is not reacted withor reactive with the multistage latex polymer.
 11. The composition ofclaim 10, wherein the silane is bis(triethoxysilylethane, 1,2bis(trimethoxysilyl)decane, (trimethoxysilyl)ethane,bis[(3-methyldimethoxysilyl)propyl]-polypropylene oxide,carboxyethylsilanetriol sodium salt,bis(2-hydroxyethyl)-3-aminopropyl-triethoxysilane,triethoxysilylmethanol, N-(triethoxysilylpropyl)-o-polyethylene oxideurethane, N-(3-triethoxysilylpropyl)gluconamide,diethylphosphatoethyltriethoxysilane,3-trihydroxysilylpropylmethylphosphonate sodium salt,3-(trihydroxysilyl)1-propane sulfonic acid, triethoxysilyl modifiedpoly-1,2-butadiene or aminoalkyl silsesquioxane oligomer.
 12. Thecomposition of claim 1, wherein the silane is epoxy-functional oramino-functional.
 13. The composition of claim 1, wherein the silane hasthe formula:R₁Si(R₂)_(3-n)(OR₃)_(n) where n is 1, 2 or 3; the R₁ group is alkyl,cycloalkyl, phenyl, cycloalkylalkyl, alkenylcycloalkyl, alkenylphenyl,or phenylalkyl, wherein R₁ contains at least one functional group andcan optionally include a silane oligomer; each R₂ group is independentlyhydrogen, alkyl, cycloalkyl, phenyl, cycloalkyl-alkyl,alkenylcycloalkyl, alkenylphenyl, phenylalkyl, or a silane oligomer,wherein each R₂ group can optionally include OR₃ groups or a functionalgroup; and each R₃ group is independently hydrogen, alkyl, cycloalkyl,phenyl, cycloalkylalkyl, alkenylcycloalkyl, alkenylphenyl, orphenylalkyl.
 14. The composition of claim 1, wherein the silane isβ-(3,4 epoxycyclohexyl)-ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-glycidoxypropylmethyldimethoxysilane, 5,6-epoxyhexyltriethoxysilane,or a hydrolyzate or mixture thereof.
 15. The composition of claim 1,wherein the silane is trimethoxysilylpropyldiethylenetriamine,N-methylaminopropyltrimethoxysilane,aminoethylaminopropylmethyldimethoxysilane,aminoethylaminopropyltrimethoxysilane, aminopropylmethyldimethoxysilane,aminopropyltrimethoxysilane, polymeric aminoalkylsilicone,aminoethylaminoethylaminopropyl-trimethoxysilane,aminopropylmethyldiethoxysilane, aminopropyltriethoxysilane,4-aminobutyltriethoxysilane, oligomeric aminoalkylsilane,m-aminophenyltrimethoxysilane, phenylaminopropyltrimethoxysilane,1,1,2,4-tetramethyl-1-sila-2-azacyclopentane,aminoethylaminopropyltriethoxysilane,aminoethylaminoisobutylmethyldimethoxysilane,benzylethylenediaminepropyltrimethoxysilane, or a hydrolyzate or mixturethereof.
 16. The composition of claim 1, wherein the silane is a silanecoupling agent.
 17. The composition of claim 1, wherein the silane hasan average molecular weight of from about 140 to about 500 g/mole. 18.The composition of claim 1, wherein the silane is at least about 0.2%and less than about 10% of the latex polymer weight.
 19. The compositionof claim 1, wherein the water-soluble acid or salt has a watersolubility of at least 5 wt. %.
 20. The composition of claim 1, whereinthe water-soluble acid or salt is completely water miscible.
 21. Thecomposition of claim 1, wherein the acid is inorganic.
 22. Thecomposition of claim 1, wherein the acid is organic.
 23. The compositionof claim 1, wherein the water-soluble acid or salt is a carboxylic,sulfonic, phosphorus, nitric, nitrous; hydrogen halide or mineral acidor salt thereof.
 24. The composition of claim 1, comprising a sodium,potassium or ammonium salt of the water-soluble acid.
 25. Thecomposition of claim 1, comprising a magnesium, calcium or iron salt ofthe water-soluble acid.
 26. The composition of claim 1, comprising amixture of water-soluble acid, acid anhydride or salt which buffers thecoating composition pH.
 27. The composition of claim 1, wherein thecomposition contains about 1 to about 40 wt. % acid, acid anhydride orsalt.
 28. The composition of claim 1, wherein the composition has a pHof about 5 to about
 9. 29. The composition of claim 1, wherein thecomposition is alkaline.
 30. A method for preparing a coated article,which method comprises providing a cementitious substrate, coating atleast a portion of the substrate with an aqueous coating compositioncomprising a multistage latex polymer; silane; and a water-soluble acid,acid anhydride or acid salt, and allowing the coating composition toharden.
 31. A coated article comprising a cementitious substrate havingat least one major surface on which is coated a layer comprising anaqueous coating composition comprising a multistage latex polymer;silane; and a water-soluble acid, acid anhydride or acid salt.